From portage 2.0.47:
* NOTICE: The wheel group requirement for non-root users has been changed to
* group portage. Group portage must be a valid group for user to use portage.
[...]
* The 2.0.47 line of portages contains an optional userpriv mode that
* enables portage to drop root privleges and run as a normal user. It is
* enabled via FEATURES by adding userpriv.

That passage has been misinterpreted a bit. It does not mean that any new portage operations can be done by non-root users. In the past, non-root users could do "emerge -s", "emerge -S", and "emerge -p", but they had to be in the wheel group. Now (meaning Portage >=2.0.47) they can do these things, but they have to be in the portage group instead. To actually install software using emerge, you still must run emerge as root. What userpriv does is internally drop permissions to the portage user to do the compilation, but the live merging onto your filesystem still must be done by root, and therefore emerge must be run as root._________________For every higher wall, there is a taller ladder

*** You are not in the portage group. You may experience cache problems
*** due to permissions preventing the creation of the on-disk cache.
*** Please add this user to the portage group if you wish to use portage.

Is this a bug with emerge. How come it thinks I'm not in the portage group. Why does it work ok if I've su'd to the user through root's account?

It works ok after an su to your user accound because su dumps you into a new shell. the old one you had before adding youself to the portage group will not work. you will need to log out and back in again for the group change to take affect._________________tercel on irc.freenode.net